The IP protective type standardized internationally for many decades indicates the suitability of electric operating means for various defined environmental conditions and ensures the protection of persons against potential danger from an electric shock during their use.
In many electrical applications electrical and electronic devices must function safely and reliably under difficult environmental conditions for many years. Aside from the admissible temperature, the corrosive load, which includes the resistance to aggressive media in the industry such as moisture, water, vapors, acids, lyes, oil or fuels, represents a limitation of use.
Moreover, the contacting and/or the penetration of foreign bodies and of dust as well as the contamination by bacteria and viruses (in medical technology) or the mechanical load by the effect of impacts must be prevented for a reliable functioning and a safe usage.
The IP protective types are defined in a standardized manner in the IEC/EN 60529. Two characterizing digits are added to the letters IP which are always present in the designation of the protective type. They show which protective scope a housing offers regarding contact and/or foreign bodies (first characterizing digit) and moisture and/or water (second characterizing digit).
The international standard EN 60034-part 5 and/or the concordance VDE 0530-5 applies for the division of the protective types of rotating electrical machines through a housing. It sets the requirements on the housings which is suitable in every other regard for their intended usage and insure regarding the materials and working that the qualities indicated in the standard are preserved during usage in accordance with the regulations.
A generic electromotor is described in DE 103 13 274 A1. It concerns in particular a motor with a motor housing that is substantially closed or encapsulated with a protective type. The electromotor consists of a stator and of an outer rotor surrounding the stator from one side in a cup-like manner as part of the motor housing and of an electronic housing which contains control electronics following as a further part of the motor housing the side axially opposite the outer rotor. The motor housing is constructed to be substantially closed or encapsulated.
In this electromotor the electronic housing comprises an opening for the electrical connection, wherein this opening can be tightly closed with a connection plug connector connected to outer connection lines. However, it was previously always the case with such known motors that permanently connected, in particular welded lines were provided for all inner connections, as was also the case in EP 2 226 922 A1.
A disadvantage is the fact that such constructions have, as is known, a tightness which is not permanently reliable and that moisture can penetrate under certain operating conditions into the motor housing, which is to be avoided.
EP 2 043 234 A1 shows a solution for this in which the electronics housing is sealed by appropriate sealing planes and sealing agents. It is provided to this end that all inner electrical connections between the connection device and the control electronics and/or between the control electronics and the stator interconnection arrangement are constructed as plug connections which are preferably aligned as regards their plugging direction and their loosening direction according to a motor axis and axially parallel to it, wherein the plug connections between the control electronics and the stator interconnection device extend through a separating wall of a stator flange in a sealing manner.
Furthermore, a connection device which comprises an intermediate carrier as terminal box is provided which carries connection contacts for the outer connection lines and contact elements of the plug connections for the control electronics, wherein the intermediate carrier comprises several seals for the sealing contact on the wall of the electronic housing in the area of through contact openings of the wall of the electronics housing. The terminal box is provided with a flat plug and inserted into a terminal box receptacle formed in the housing. Therefore, depending on the construction type, several sealing ranges provided in the axial direction are disadvantageously provided in different sealing planes.
It is therefore desirable to avoid a series of disadvantages resulting from this. Since every seal has application-specific sealing problems, it is advantageous to generally reduce the number of seals. Furthermore, when coordinating various combined structural components and structural components of an electronics unit the tolerances and resulting tolerance chains can only be managed with high costs. It is necessary, in particular in the case of several sealing planes present in an axial direction to exactly coordinate with one another the tolerances of the structural components contributing to the seal and the configuration of the seals.
Furthermore, there is no seal to the printed circuit board and therefore to the control electronics as long as or as soon as the terminal box has not been mounted or dismounted.
It is furthermore desirable to reduce the number of plug connections and accordingly the number of contact transitions. A transition resistance and therefore the development of heat is associated with each contact transition. Furthermore, it is disadvantageous in the previously cited solution that the risk of damage to the contacts occurs. Therefore, it can occur that the plug pins (signal contacts) as well as the maintenance connection contacts can be bent or damaged during transport, the mounting and/or, e.g., during the handling of the connection wiring. Therefore, a certain mounting sequence is also necessary when “blindly” joining when combining the structural parts.
The high number of structural components in the complex construction are furthermore disadvantageous in the solutions known in the prior art.